CODEWITHSUNDEEP
c#visual-studio
AlpHA
AlpHA

Reputation: 13

Subtraction, Multiplication and Division script not working properly

I have this code, which is a part of a calculator I am currently making.

class Program
{
    static void Main(string[] args)
    {
        string a = "6-3";/*This is supposed to be entered in a textbox by a user*/

        int b = a.IndexOf(("-"));

        string c = a.Substring(0, b);

        int num1 = Convert.ToInt32(c);

        int b2 = a.IndexOf(("-"));
        string c2 = a.Substring(b);
        int num2 = Convert.ToInt32(c2);
        if(a.Contains("-"))
        {
            int an = num1 - num2;
            string ans = Convert.ToString(an);
            Console.WriteLine(ans);
        }
    }
}

The problem is that this results in 9 instead of 3, which it is supposed to output. And if i try the exact same code with division or multiplication the program crashes. Strange as it may seem, the code works perfectly with addition. Any help?

Upvotes: 1

Views: 98

Answers (3)

TvanB
TvanB

Reputation: 112

that's because you make a substring of -3, not 3. string c2 = a.Substring(b); should be string c2 = a.Substring(b+1);

a shorter version of this would be:

if(a.Contains("-")) 
{
    string[] nums = a.split('-')
    Console.WriteLine( ((int)nums[0]) - ((int)nums[1]) )
}

Upvotes: 0

Equalsk
Equalsk

Reputation: 8224

It's because of this line:

 string c2 = a.Substring(b);

c2 is equal to "-3" and so converts to -3. 6 - -3 is 9.

Change the line to this:

 string c2 = a.Substring(b + 1);

There are numerous other problems, the code needs serious refactoring but that's off topic a little.

Upvotes: 2

Dispersia
Dispersia

Reputation: 1438

When you substring c2, b is 1. "6-3".Substring(1) will return -3. The substring parameters first input is how far forward to move. You need to move the index + 1 to move past the operator.

This makes your math problem 6 - - 3

Upvotes: 1

Related Questions